Abstract
Purpose: :
To test whether the location of visual field (VF) loss at diagnosis is associated with progression in VF loss over time.
Methods: :
Humphrey 24-2 full threshold VF tests taken at baseline in the CIGTS on 607 enrolled subjects with newly-diagnosed open-angle glaucoma were inspected for location of VF loss. Each point of the total deviation probability plot was given a score of 0 to 4 based on the level of significant depression relative to the normal Humphrey database (0: p≥0.05; 1: 0.02≤p<0.05; 2: 0.01≤p<0.02; 3: 0.005≤p<0.01; 4: p<0.005). VF loss was defined as the average score of points within a location. VF locations that were evaluated included central points, paracentral points, quadrants, hemifields, and peripheral field areas. Analyses relied on a previously published regression model that identified key baseline factors predictive of long-term VF loss in the CIGTS (Musch DC et al., Ophthalmology 2009; 116:200-7). Variables for VF loss in unique areas were added to the baseline regression model to test whether the added location factor was significantly associated with longitudinal VF loss. Combinations of locations were also tested for significant associations with VF loss over time. SAS 9.2 Proc Mixed software was used.
Results: :
Paracentral VF loss at baseline was consistently the most predictive of subsequent VF loss among all locations and combinations that were evaluated. Every one unit increase in paracentral loss was associated with a decrease in mean deviation (MD) of 1.7dB (p<0.0001). VF loss in several peripheral regions was found to be associated with moderate improvement/less worsening of MD, which may have resulted from artifactual change in the baseline VF tests. Associations between baseline location of VF loss and follow-up location of loss will also be presented.
Conclusions: :
In the CIGTS, specific locations of VF loss at diagnosis were predictive of more or less worsening in subsequent VF over time. Paracentral loss was shown to be strongly associated with a decrease in VF over time. Assessment of location of VF loss at diagnosis may have implications for how aggressive a patient should be treated.
Keywords: clinical (human) or epidemiologic studies: risk factor assessment • visual fields